As a kid growing up in Marin County, Tyler Mitchell’s favorite thing was going to the movies.

“I always loved them,” he says. “I watched movies incessantly.”

When it came time to choose a career, the 29-year-old Branson School grad ended up doing the Marin thing: following his bliss.

He went to Duke University, majoring in economics. And while his classmates were becoming investment bankers and stock brokers and money managers, he went off to Hollywood to learn the movie business.

“I packed up my car and drove out to L.A.,” he says. “I knew nothing. I didn’t even know what a gaffer was.”

Mitchell started as an intern for producers like Chris Baker and J.C. Spink (“American Pie,” “The Ring,” “A History of Violence”), fetching coffee, reading scripts, an eager go-fer soaking up everything he could about the industry.

“I was working 10 to 12 hours a day for no money, and yet I loved every second of it,” he says from his West Hollywood home. “It didn’t feel like work to me at all. That’s when I knew that if I could get paid to do this, that would be a dream. And that’s how it all started.”

Now an up-and-coming young Hollywood producer, Mitchell has his first major movie in theaters, the violent comic thriller “Lucky Number Slevin,” starring heartthrob Josh Hartnett, love interest Lucy Liu and the ubiquitous A-list actors Bruce Willis, Morgan Freeman, Stanley Tucci and Ben Kingsley.

Mitchell has worked on several other movies, but “Slevin” is his debut as the lead producer. And he will be the first to tell you that it has not been easy. Shepherding the independent picture from script to screen has taken five years.

“You feel like Sisyphus pushing that boulder up the hill,” he says. “It’s a constant grind. Getting a movie going from the ground up is a huge task.”

That “Slevin” got made at all is testament to his tenacity and talent. All the major studios passed on screenwriter Jason Smilovic’s script before Mitchell read it, thought it was “a needle in the haystack” in the “Pulp Fiction”/”Get Shorty” genre, and started pushing the boulder up the hill.

Late in the game, though, while in Montreal scouting locations and hiring a crew, he nearly had to abandon the project when his complex web of financing began to unravel.

“The financiers were saying that without another star in the cast, they weren’t going to finance the movie,” he recalls. As luck would have it, Willis and Freeman came to the rescue, signing on within a couple of days of each other.

“I used to get really worked up about things like that all the time,” he says. “But it’s such an emotional roller coaster that at some point you have to let it go and believe that things will come together. Because, if you don’t, you will drive yourself crazy.”

With Paul McGuigan (“Gangster Number One”) directing, “Slevin” was shot in 43 days last winter in Montreal, Toronto and New York.

The budget ended up at $27 million, “less than Tom Cruise is being paid for ‘Mission Impossible 3’ by a long shot,” he says.

It’s a clich}, but for a producer in Hollywood, there really is no rest for the weary. After his movie was in the can, Mitchell still had to market it and deal with the reviews, many of which have been less than kind.

“They are the most polarized reviews I’ve ever seen,” he says. “You’ve got Gene Shalit saying it’s the best movie of 2006 and you’ve got Roger Ebert and the New York Times slamming it. But I’d rather have a film that some people love and some people hate than everyone thinks is just OK.”

The problem is that, so far, there haven’t been enough people on the love side of the equation. “Slevin” did a modest $7 million at the box office when it opened last weekend, finishing fifth.

“It’s discouraging because a lot of people say it’s too clever for its own good, or it’s a ‘Pulp Fiction’ rip-off,” he says. “The critics supposedly represent people who care about film and want to see smart movies getting made, yet they’re so harsh on a movie that was independently financed, that the studios didn’t want to make, that we at least tried to make smart and engaging. It just fosters more down-the-middle generic films being pumped out by the studios.

To back up his argument, he points to “Benchwarmers,” the John Heder/Rob Schneider/David Spade baseball comedy.

“It made $20 million last weekend,” Mitchell says. “I guarantee you that everyone in Hollywood today is saying, ‘We’ve got to find another broad comedy. We’ve got to make cheap comedies.'”

Despite whatever disappointment he may feel, Mitchell sounds positive and levelheaded. He’s been married to Branson schoolmate Brooke Siebel Mitchell for two years. “She’s not in the business,” he says. “She keeps me really grounded.”

And he’s formed a new production company, Dark and Stormy Entertainment, with Smilovic, the screenwriter who wrote “Slevin,” and fellow producer Robert Kravis. They have several movies and a TV series in the works.

Mitchell admits that the Hollywood lifestyle is often like “Entourage,” the HBO series that nails the crassness of the movie culture. But that doesn’t mean that everyone buys into it. He hasn’t.

“For so many people who come to Los Angeles, the movie business is so difficult and so competitive that their whole life becomes Hollywood,” he says.

“At one point, I thought maybe that’s what I wanted. And I’m not going to lie to you, some of it did seem very glamorous. But, after being out here for a year or two, you see through it. I have another life completely away from the business. I have the best of both worlds.”